Electrochemical synthesis of polypyrrole films doped by ferrocyanide ions onto iron substrate: Application in the electroanalytical determination of uric acid

Hollow spherical micro-particles of polypyrrole film doped by ferrocyanide anions Fe(CN)63− were synthesized by chronoamperometric mode at 750 mV/(Ag/AgCl) onto iron substrate from an aqueous solution containing pyrrole monomer, potassium hexacyanoferrate K4Fe(CN)6 and potassium tetraoxalate (C4H3KO8). The modified electrode PPy/FCN/Fe was characterized by XRD, FEG-SEM and EDX techniques and its electrochemical behavior toward uric acid oxidation was studied by cyclic voltammetry. The results show that the incorporation of Fe(CN)63− anions into the polypyrrole matrix improves significantly the electrocatalytic activity of this film. The plot of the catalytic oxidation peak current as function of uric acid concentration gives rise to the obtaining of straight line with a correlation coefficient of 0.983 and a good sensitivity of 4.46 μA/mM. The detection limit was found to be equal to 23 μM in a wide range of uric acid's concentration.